Variation in the promotor region of the serotonin transporter gene (5-HTTLPR) is a promising candidate for better understanding individual heterogeneity in subjective well-being or happiness, as measured by life satisfaction. This functional polymorphism has previously been associated with mental health and selective processing of positive and negative emotional stimuli. A case–control association study on a representative sample of Americans (N¼2574) finds that individuals with the transcriptionally more efficient version of the serotonin transporter gene, report significantly higher levels of life satisfaction (P¼0.01). This new finding may help explain the important genetic component of the individual baseline levels of happiness.

We explore the influence of genetic variation on subjective well-being by employing a twin design and genetic association study. In a nationally representative twin sample, we first show that 33% of the variation in life satisfaction is explained by genetic variation. Although previous studies have shown that baseline happiness is significantly heritable, little research has considered molecular genetic associations with subjective well-being. We study the relationship between a functional polymorphism on the serotonin transporter gene(5-HTTLPR) and life satisfaction. We initially find that individuals with the longer, transcriptionally more efficient variant of this genotype report greater life satisfaction (n = 2,545; p .012). However, our replication attempts on independent samples produce mixed results, indicating that more work needs to be done to better understand the relationship between this genotype and subjective well-being. This work has implications for how economists think about the determinants of utility, and the extent to which exogenous shocks might affect individual well-being.